286 lines
8.0 KiB
C#
286 lines
8.0 KiB
C#
/*
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Copyright (C) 2011-2015 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System;
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using System.Collections.Generic;
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using System.IO;
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using dnlib.IO;
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using dnlib.DotNet;
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using dnlib.DotNet.Emit;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.CodeVeil {
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class ProxyCallFixer : ProxyCallFixer1 {
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MainType mainType;
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Info info = new Info();
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IBinaryReader reader;
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class Info {
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public TypeDef proxyType;
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public MethodDef initMethod;
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public FieldDef dataField;
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public TypeDef ilgeneratorType;
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public TypeDef fieldInfoType;
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public TypeDef methodInfoType;
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}
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class Context {
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public int offset;
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public Context(int offset) {
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this.offset = offset;
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}
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}
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public bool FoundProxyType {
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get { return info.proxyType != null; }
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}
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public bool CanRemoveTypes {
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get {
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return info.proxyType != null &&
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info.ilgeneratorType != null &&
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info.fieldInfoType != null &&
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info.methodInfoType != null;
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}
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}
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public TypeDef IlGeneratorType {
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get { return info.ilgeneratorType; }
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}
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public TypeDef FieldInfoType {
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get { return info.fieldInfoType; }
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}
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public TypeDef MethodInfoType {
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get { return info.methodInfoType; }
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}
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public ProxyCallFixer(ModuleDefMD module, MainType mainType)
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: base(module) {
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this.mainType = mainType;
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}
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public ProxyCallFixer(ModuleDefMD module, MainType mainType, ProxyCallFixer oldOne)
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: base(module, oldOne) {
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this.mainType = mainType;
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info.proxyType = Lookup(oldOne.info.proxyType, "Could not find proxyType");
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info.initMethod = Lookup(oldOne.info.initMethod, "Could not find initMethod");
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info.dataField = Lookup(oldOne.info.dataField, "Could not find dataField");
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info.ilgeneratorType = Lookup(oldOne.info.ilgeneratorType, "Could not find ilgeneratorType");
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info.fieldInfoType = Lookup(oldOne.info.fieldInfoType, "Could not find fieldInfoType");
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info.methodInfoType = Lookup(oldOne.info.methodInfoType, "Could not find methodInfoType");
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}
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protected override object CheckCctor(ref TypeDef type, MethodDef cctor) {
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var instrs = cctor.Body.Instructions;
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for (int i = 0; i < instrs.Count - 1; i++) {
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var ldci4 = instrs[i];
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if (!ldci4.IsLdcI4())
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continue;
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var call = instrs[i + 1];
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if (call.OpCode.Code != Code.Call)
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continue;
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if (call.Operand != info.initMethod)
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continue;
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int offset = ldci4.GetLdcI4Value();
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reader.Position = offset;
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uint rid = reader.ReadCompressedUInt32();
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if (rid != type.Rid)
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throw new ApplicationException("Invalid RID");
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return string.Empty; // It's non-null
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}
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return null;
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}
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protected override void GetCallInfo(object context, FieldDef field, out IMethod calledMethod, out OpCode callOpcode) {
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byte flags = reader.ReadByte();
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int methodToken = 0x06000000 + ((flags & 0x3F) << 24) + (int)reader.ReadCompressedUInt32();
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int genericTypeToken = (flags & 0x40) == 0 ? -1 : 0x1B000000 + (int)reader.ReadCompressedUInt32();
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callOpcode = (flags & 0x80) != 0 ? OpCodes.Callvirt : OpCodes.Call;
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calledMethod = module.ResolveToken(methodToken) as IMethod;
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if (calledMethod == null)
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throw new ApplicationException("Could not find method");
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if (genericTypeToken != -1 && calledMethod.DeclaringType.MDToken.ToInt32() != genericTypeToken)
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throw new ApplicationException("Invalid declaring type token");
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}
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public void FindDelegateCreator() {
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if (!mainType.Detected)
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return;
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var infoTmp = new Info();
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if (!InitializeInfo(infoTmp, mainType.Type))
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return;
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info = infoTmp;
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SetDelegateCreatorMethod(info.initMethod);
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}
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bool InitializeInfo(Info infoTmp, TypeDef type) {
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foreach (var dtype in type.NestedTypes) {
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var cctor = dtype.FindMethod(".cctor");
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if (cctor == null)
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continue;
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if (!InitProxyType(infoTmp, cctor))
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continue;
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return true;
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}
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return false;
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}
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bool InitProxyType(Info infoTmp, MethodDef method) {
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foreach (var calledMethod in DotNetUtils.GetCalledMethods(module, method)) {
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if (!calledMethod.IsStatic)
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continue;
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if (!DotNetUtils.IsMethod(calledMethod, "System.Void", "(System.Int32)"))
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continue;
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if (!CheckProxyType(infoTmp, calledMethod.DeclaringType))
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continue;
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infoTmp.proxyType = calledMethod.DeclaringType;
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infoTmp.initMethod = calledMethod;
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return true;
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}
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return false;
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}
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static string[] requiredFields = new string[] {
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"System.Byte[]",
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"System.Int32",
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"System.ModuleHandle",
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"System.Reflection.Emit.OpCode",
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"System.Reflection.Emit.OpCode[]",
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};
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bool CheckProxyType(Info infoTmp, TypeDef type) {
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if (type.NestedTypes.Count != 1)
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return false;
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if (!new FieldTypes(type).All(requiredFields))
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return false;
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var fields = GetRvaFields(type);
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if (fields.Count != 1)
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return false;
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var field = fields[0];
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var fieldType = DotNetUtils.GetType(module, field.FieldSig.GetFieldType());
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if (type.NestedTypes.IndexOf(fieldType) < 0)
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return false;
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if (field.InitialValue == null || field.InitialValue.Length == 0)
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return false;
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infoTmp.dataField = field;
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return true;
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}
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static List<FieldDef> GetRvaFields(TypeDef type) {
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var fields = new List<FieldDef>();
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foreach (var field in type.Fields) {
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if (field.RVA != 0)
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fields.Add(field);
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}
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return fields;
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}
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protected override IEnumerable<TypeDef> GetDelegateTypes() {
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if (!mainType.Detected)
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return new List<TypeDef>();
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return mainType.Type.NestedTypes;
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}
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public void Initialize() {
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if (info.dataField == null)
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return;
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FindOtherTypes();
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var decompressed = DeobUtils.Inflate(info.dataField.InitialValue, true);
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reader = MemoryImageStream.Create(decompressed);
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info.dataField.FieldSig.Type = module.CorLibTypes.Byte;
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info.dataField.InitialValue = new byte[1];
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info.dataField.RVA = 0;
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}
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void FindOtherTypes() {
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if (info.proxyType == null)
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return;
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foreach (var method in info.proxyType.Methods) {
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var sig = method.MethodSig;
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if (sig == null || sig.Params.Count != 4)
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continue;
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if (sig.Params[2].GetFullName() != "System.Type[]")
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continue;
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var methodType = sig.Params[0].TryGetTypeDef();
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var fieldType = sig.Params[1].TryGetTypeDef();
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var ilgType = sig.Params[3].TryGetTypeDef();
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if (!CheckMethodType(methodType))
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continue;
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if (!CheckFieldType(fieldType))
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continue;
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if (!CheckIlGeneratorType(ilgType))
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continue;
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info.ilgeneratorType = ilgType;
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info.methodInfoType = methodType;
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info.fieldInfoType = fieldType;
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}
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}
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bool CheckMethodType(TypeDef type) {
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if (type == null || type.BaseType == null || type.BaseType.FullName != "System.Object")
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return false;
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if (type.Fields.Count != 1)
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return false;
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if (DotNetUtils.GetField(type, "System.Reflection.MethodInfo") == null)
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return false;
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return true;
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}
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bool CheckFieldType(TypeDef type) {
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if (type == null || type.BaseType == null || type.BaseType.FullName != "System.Object")
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return false;
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if (DotNetUtils.GetField(type, "System.Reflection.FieldInfo") == null)
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return false;
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return true;
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}
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bool CheckIlGeneratorType(TypeDef type) {
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if (type == null || type.BaseType == null || type.BaseType.FullName != "System.Object")
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return false;
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if (type.Fields.Count != 1)
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return false;
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if (DotNetUtils.GetField(type, "System.Reflection.Emit.ILGenerator") == null)
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return false;
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return true;
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}
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}
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}
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